Escapement mechanism



April 9, 1968 c K 3,376,754

ESCAPEMENT MECHANISM Filed Dec. 1, 1965 INVENTOR= CLEMENT .DOCK

United States Patent Ofiice 3,376,754 ESCAPEMENT MECHANISM Clement A. Dock, Philadelphia, Pa., assignor to the United States of America as represented by the Secretaryof the Army Filed Dec. 1, 1965, Ser. No. 511,303 2 Claims. (Cl. 74--1.5)

ABSTRACT OF THE DISCLOSURE the wire end portions are slidably mounted in a circular hole in corresponding support members, by which operative friction loss is minimized.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to escapement mechanisms and, more particularly, to an improved escapement for timing mechanisms of munition fuzes.

It is an object of the invention to provide an escapement mechanism which is of maximum reliability in that the chance of hairspring fracture is substantially eliminated, and the spring ends are subjected to a minimum amount of friction which is insufiicient to adversely effect the frequency of the spring.

Another object of the invention is to provide such a mechanism in which a positive controlled movement of the escapement lever pallets insures a smoothly functioning, uniform depth of lock engagement with the escapement gear teeth.

A further object of the invention is to provide an escapement mechanism having a minimum spin sensitivity.

In one aspect of the invention the mechanism comprises pallet means integral with an escapement lever to control escapement gear movement, an escapement spring to control the beat frequency of the lever, and lever limiting pins positioned on either lateral side of an arm of the lever.

In other aspects of the invention, the hairspring is in form of a round wire secured by a tubular plug to an arbor, the wire ends being slidably mounted in circular holes of respective support members.

These and other objects, features and advantages of the invention will become more apparent from the following description and accompanying drawings in which:

FIG. 1 is a perspective view of an escapement mechanism embodying the principles of the invention.

FIG. 2 is an elevational view, transversely of the hairspring and partially broken away in section, of the arbor arrangement in FIG. 1.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is an enlarged sectional view of the arbor support plug employed in FIGS. 1 to 3 to secure the hairspring in its desired position.

The escapement gear 11 (FIG. 1) has an integral pinion gear 12 which is connected by an appropriate gear train to a pre-set stored energy fuze timing device (not shown), such that gradual, substantially constant speed rotation of Patented Apr. 9, 1968 gear 11, as controlled by oscillatory motion of pallets 13, 13 that alternately engage successive teeth 14 on gear 11, will release the timer stored energy to actuate an armed, munition firing pin or other predetermined events (not shown) or complete an electric circuit (not shown) as is well known by those skilled in the art.

Both the escapement pinion pivots 15, 15 and arbor pivots 16, 16 (FIGS. 1, 2, 3) are journalled between the same pair of spaced, upper and lower lamina plates 17, 18 (FIG. 2) of the timing fuze mechanism. The escapement lever 19 and integral pallets 13, 13 are rigidly secured by suitable means to a rotatable on pivotable arbor 20 which in turn rigidly supports the central portion of a round wire escapement spring 21. The ends of the round wire or hairspring 21 extend through and are slidably supported in appropriate circular openings 22 in respective adjusting nuts or supports 23. Nuts 23 have threaded apertures 24 and are radially adjustable along a corresponding threaded member (not shown) longitudinally of the wire 21 to predeterminedly set the beat frequency of the hairspring 21. The ends of the round wire, sliding through their slightly larger support apertures, are subjected to a minimum amount of friction that is insufiicient to adversely effect the frequency of the spring.

Lever limiting pins 25, 25 secured to either or both of plates 17, 18 at predetermined spaced positions and extend past the lateral edges of escapement lever arms 19A so as to function as a pair of stops for arm 19A and limit the oscillation of the lever 19 and its pallets 13, 13 in a positive controlled movement that insures a smoothly functioning, uniform depth of lock engagement with the escapement gear teeth 14.

The use of a round wire escapement spring 21 provides the mechanism with minimum spin sensitivity when operating in a high speed rotational environment, such as within a spinning projectile. The central or mid-length portion of the wire 21 is received with a close fit within a tubular brass plug member 28 (FIGS. 2, 3, 4), the tubular plug 28 having been press-fitted into a longitudinally extending arbor bore 29 (FIGS. 2, 3), the arbor 20 having been provided with a transverse bore 36 (FIG. 2) which is smaller than and intersects bore 29. Bore 30 thus can accommodate a punch or equivalent tool to deform portions 31, 32 of the plug sidewall (dotted lines in FIG. 4) to lock the round wire escapement spring in its desired position. This manner of mounting a round wire escapement spring in which the chance of hairspring fracture has been substantially eliminated provides an improved escapement mechanism that is of maximum reliability.

Various modifications, alterations or changes may be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. In a timing mechanism having pallet means for controlling the movement of an escapement gear,

an escapement lever integral with said pallet means,

an escapement spring for controlling the beat frequency of said lever, said spring being in the form of a round Wire for obtaining a minimum of spin sensitivity, said Wire being supported at its mid-length by a pivotal arbor construction, said arbor having a through bore and a transverse opening intersecting with said bore, a tubular brass plug extending through said bore and surrounding the mid-length of said wire, said plug being secured to both said arbor and wire, and lever limiting pins positioned in predetermined positions on either lateral side of an arm of said lever,

so constructed and arranged that said limiting pins uniformly control the movement of said pallet means in the engagement thereof with said gear.

2. The structure defined in claim 1 wherein end portions of said round wire are slidahly mounted in respective apertured support members, the corresponding apertures of which being defined by circular holes therein, to produce minimum operative frictional losses between said wire end portions and their support members.

4 References Cited j' .3 UNITED STATES PATENTS 1,913,991 6/1933 Lux 58-117 3,168,833 2/1965 Popovitch 74-1.5

MILTON KAUFMAN, Primary Examiner. 

